Method for producing molded articles having inserts incorporated therein

ABSTRACT

A method for manufacturing a molded article having an insert incorporated therein comprises the steps of providing a first mold half having a mold core portion and a second mold half having a mold cavity portion, providing a carrier plate having a holder for an insert and a device for receiving the molded article located on the same face, positioning the carrier plate with the insert thereon between the first and second mold halves when the first and second mold halves are in an open position so that the insert is aligned with the mold core portion, transferring the insert to a position adjacent the mold core portion, withdrawing the carrier plate from between the first and second mold halves, moving the first and second mold halves together so that the mold cavity portion substantially surrounds at least a portion of the insert and defines a mold cavity space with the mold core portion, and injecting molten material into the mold cavity space so as to form the molded article.

This is a division of application Ser. No. 08/229,007, filed Apr. 18,1994, now U.S. Pat. No. 5,527,173.

BACKGROUND OF THE INVENTION

The invention relates to an improved apparatus and method for removingmolded articles from a multi-cavity injection mold and loading insertsinto the cavity of the same mold. The apparatus and the method of thepresent invention have particular utility in the manufacture oflaminated plastic containers suitable for holding foods, beverages andchemicals.

The art of molding through, around or adjacent inserts placed in aninjection molding cavity are well known in the injection moldingindustry. A number of different methods have been developed to load theinserts to be included within the molded article and to unload themolded article from the machine. Typically, the method that is used fora particular molding system takes into account the size, shape andnumber of the inserts to be loaded and such other factors as cost,degree of automation, complexity, speed and reliability.

For example, U.S. Pat. No. 3,837,772 to Van de Walker et al. illustratesa top entry robot system which is fed with inserts which are held inplace on the robot using a vacuum. Upon opening the mold, a transferplate moves into position opposite core pins in the mold. When thetransfer plate is in this position, the vacuum is substituted by apressure which forces the inserts onto the core pins where they are heldin place by a vacuum applied to the core pins. If the inserts areopen-ended, this vacuum method may not be feasible or effective.

U.S. Pat. No. 4,648,825 to Heil et al. illustrates a different systemhaving a horizontal gantry structure which spans perpendicularly acrossthe injection machine. An arm which depends from one end of the gantrysecures a load carrier while another arm depending from the opposite endof the gantry secures an unload carrier. The arms move toward each otherwhen the mold is opened to perform the loading and unloading functions.This approach disadvantageously requires two tooling arms, occupiessubstantial floor space on both sides of the machine, and is verycostly.

European patent document No. 0 357 777 to Orimoto et al. shows a plasticmouth insert which is loaded into the injection mold. The purpose ofthis insert is to provide heat resistance in the neck finish area whichis required during subsequent operations in making a container. Asdiscussed in this patent document, it is advantageous to accuratelycenter the insert in the cavity and to support it in place as theinjected plastic flows around it. For the purpose of loading the insertinto the injection mold, it is recommended to position the insert inplace between the mold splits, then close the splits in the conventionalmanner. In some cases, it may not be feasible or practical to deliverthe insert from the carrier plate to its final position in the mold dueto space restrictions or alignment problems and a co-operative effortfrom both carrier plate and mold are essential. Where molds alreadyemploy the use of moving mold ejection components, the return stroke ofthe components can provide the double function of insert retrieval,saving redundant motion and time. Hence, the loading device should alsobe capable of working in concert with the most advanced molds aspreviously discussed, which incorporate non-rectilinear mold splitsmotion.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention toprovide an improved molding apparatus which uses a single compactcarrier plate for the loading of mold inserts and the unloading ofmolded articles.

It is a further object of the present invention to provide an improvedmolding apparatus as above which mechanically interacts with a carrierplate insert loading device to effectively aid in the reception andlodgment of an insert in the mold cavity space prior to injection.

It is still a further object of the present invention to provide animproved molding apparatus as above which actively grips and holds orcontains an insert in the cavity space.

It is yet a further object of the present invention to provide animproved process for molding an article wherein inserts can be morereadily inserted into the mold cavity and molded articles can beunloaded.

Still further objects and advantages to the present invention willbecome more apparent from the following description and drawings whereinlike reference elements depict like elements.

The foregoing objects and advantages may be readily obtained by theimproved molding apparatus and process of the present invention. Inaccordance with the present invention, the improved molding apparatusincludes a first mold half having one or more core portions and a secondmold half having one or more cavity portions. The first and second moldhalfs are movable between an open position and a closed position whereinsaid core and cavity portions define at least one space in the shape ofthe article to be molded. The molding apparatus further includes acarrier plate for receiving the molded article(s) after the moldingcycle has been completed and for holding the insert(s) to beincorporated into the molded article. The carrier plate is movable froma first position between the mold halfs when the mold halfs are in anopen position to a second position outside of the mold halfs. Thecarrier plate is also indexable between a first position wherereceptacle(s) for receiving the molded article(s) are aligned with themold core portion(s) and a second position wherein means for holding theinsert(s) is aligned with the mold core portion(s).

The method of the present invention broadly comprises the steps ofproviding a first mold half having a mold core portion and a second moldhalf having a mold cavity portion; placing at least one insert on saidmold core portion while said mold halfs are in an open position byaligning a carrier plate with means for holding said at least one insertwith said mold core portion and transferring said at least one insert tosaid mold core portion; withdrawing said carrier plate from between saidmold halfs; moving said mold halfs so that said mold core portion abutssaid mold cavity portion; injecting plastic material into a spacedefined by said abutted mold core and mold cavity portions to form atleast one molded article having at least one insert therein, moving saidmold halfs to a mold open position, and moving said carrier plate intosaid position between said mold halfs to remove the at least one moldedarticle.

Further details of the apparatus and method of the present invention arediscussed in the following description and drawings wherein likereference numerals depict like elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top view of an apparatus for producing plasticarticles;

FIG. 2 is an end view of a mold cavity plate and a carrier plate whenviewed in the direction "A" shown in FIG. 1 with the carrier plate beingin an outboard position;

FIG. 3 is a top view of a carrier plate in a position to load insertsonto mold core portions of the apparatus of FIG. 1 with the insertholding means shown in partial cross section;

FIG. 4 is a top view showing an insert in an extended position betweentwo mold splits;

FIG. 5 is a top view showing an insert being gripped by the mold splits;

FIG. 6 is a sectional view showing an insert in a mold closed position;

FIG. 7 illustrates an alternative embodiment of an insert to beincorporated into a molded article and an alternative device for holdingsaid insert; and

FIG. 8 illustrates the insert of FIG. 7 in a mold closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawings, FIG. 1 illustrates an apparatus forproducing plastic articles in accordance with the present invention. Theapparatus includes a molding machine 10 preferably comprising amulticavity machine. The number of cavities and the arrangement thereofshown in FIG. 1 are exemplificative only. It should be recognized thatany convenient number of cavities and any suitable arrangement of thecavities may be employed in the machine 10. In fact, one could use asingle cavity arrangement, although multicavity arrangements arepreferred for economic reasons.

The machine 10 includes a first mold half 11 which is a cavity half anda second mold half 12 which is a core half. The first mold half 11 hasat least one cavity 13 therein and preferably a plurality of cavities13. A representative cavity arrangement is shown in FIG. 2. Thisarrangement has two spaced rows of cavities 13 with each row containingeight cavities. The second mold half 12 has at least one elongate core14 therein with the number of cores corresponding to the number ofcavities. Core(s) 14 are each engageable with a respective cavity forseating therein in a mold-closed position to form a closed mold for theformation of one or more plastic articles therein by injection molding.The number of articles formed in an injection molding cycle will dependon the number of cavities and corresponding cores. Normally, the core(s)14 reciprocate from a mold-closed position seated in said cavities forthe formation of the molded articles to a mold-open position spaced fromsaid cavities forming a gap between the cores and cavities for ejectionof the molded articles. FIG. 1 shows the first and second mold portionsin a mold open position. The mold portions 11 and 12 reciprocate on tierods 15 and may be powered by any convenient motive means known in theart, such as by hydraulic cylinder 16, in a predetermined cycle. Moltenplastic material is injected into a space 76 formed between each coreand cavity in the mold-closed position by known injection moldingprocedures.

It is preferred to retain the formed articles on cores 14 afterformation of the articles and upon reciprocation of the mold portionsfrom the mold-closed position to the mold-open position. A carrier plate20 is provided to receive the molded articles removed from the cores 14.Removal of the articles from the cores onto the carrier plate 20 may beaccomplished by blowing air through vent lines 17 and/or by the use of astripper plate 18 reciprocating on guide pins 19.

The carrier plate 20 is movable from the outboard position shown inFIGS. 1 and 2 to a position between the mold halfs 11 and 12. Anysuitable indexing means 31, 32, 33, 34, 36 and 38 known in the art maybe used to move the carrier plate 20. One such mechanism is shown inU.S. Reissue Pat. No. 33,237 to Delfer which is hereby incorporated byreference herein.

Carrier plate 20 is provided with at least one set of receivers 21 forcooling the molded plastic articles. If a longer cooling time in thereceiver is desired or needed, multiple sets of receivers, such asreceivers 21 and 22, may be employed. The carrier plate in FIG. 2includes a first set of carrier plate receivers 21 and a second set ofcarrier plate receivers 22. The carrier plate 20 also includes a set ofinsert holders 23, which are positionally arranged in like manner toreceivers 21 and 22. It should be noted that each of sets 21, 22 and 23corresponds to the arrangement of the first mold portion cavities 13,with each of said sets being spaced apart by a fixed distance.

FIG. 3 shows a top view of a carrier plate 20 having two columns or sets23 of inserts 44 in alignment with mold cores 14 having a complementaryconfiguration. Mold splits 45 mounted to the mold core half 12 are shownin a forward extended position. The mold splits 45 are fastened toslides 46 which move the mold splits 45, and a molded article held bythe mold splits, axially off a respective core 14. The article isreleased from the grasp of the mold splits through separation of sameoccurring at a point X, toward the end of the ejection stroke. Cams orother mechanical devices well known in the art may be employed todictate the exact distance the mold splits will separate from each otherand the position at which they will separate.

The carrier plate 20 has one or more mandrels 51 mounted thereto to holdinsert(s) 44. Each mandrel 51 can be made of a flexible material such asa plastic with a hollow core and serrated sides which act as fingers tospring against and hold the inside diameter of the insert 44. Eachmandrel 51 is preferably mounted on a structural channel 52 which isfastened to and positioned by actuating piston-cylinder unit 53. Thepiston-cylinder unit 53 is used to extend the channel 52 and the mandrel51 and thereby advance the insert 44 to an axial position between theopen mold splits 45. Of course, there are numerous methods for holdingan insert on an insert holder dependent on its size and shape and how itmust interact with the cooperating mold components which are to receivethe insert. This is but one example.

Adjacent the columns of insert holders 51 are the columns of receivingstations 21 and 22 which receive the molded article(s) after ejection.Bumper pads 55 are fastened to the structural channel 52 and are sizedsuch that their forward face 56 is a prescribed distance from the baseof the insert 44. As shown in FIG. 4, when the mandrel holding channel52 moves forward, the face 56 of the bumper pad 55 hits a correspondingplane on the mold split 45. The bumper pad 55 thereby defines thecorrect axial position of the insert between the mold splits. As theactuating cylinder 53 continues to push forward, the relative axialposition of both the insert 44 and the mold splits 45 are kept constant.As the mold splits 45 move inward toward the center axis of a respectivecore 14, the mold splits 45 come together to grip or envelope the insert44. To this end, each mold split 45 has a notch 70 for gripping orreceiving a portion 72 of the insert 44.

FIG. 5 shows the moment when the insert 44 is first closed upon by themold splits 45. Further movement of the mold splits to their seatedposition effectively strips the insert from the mandrel 51. After theinsert has been stripped from the mandrel 51, the carrier plate 20 ismoved from a position where the insert(s) are aligned with the moldcore(s) 14 toward the outboard position and the mold halfs 11 and 12 aremoved toward their closed position.

FIG. 6 shows an insert 44 lodged in its position in the space 76 definedby the mold core and cavity prior to injection of the plastic material.FIG. 6 also shows the manner in which the mold splits 45 areaccommodated by shaped mold cavity and mold core portions 80, 82.Plastic material is injected into the space 76 via nozzle 78. Theplastic material flows around the insert 44 and incorporates same intothe molded article being formed. After the plastic material has beencooled and solidified, the mold portions 11 and 12 are moved to theiropen position. During this opening operation, the molded article remainson the core 14. After the molds have reached the open position, thecarrier plate 20 is moved from the outboard position to a positionintermediate the mold halfs where one of the sets of receiving stationsis aligned with each mold core(s) 14. The slides 46 are then movedtoward the carrier plate 20 and the molded article is unloaded into oneof the receiving stations 21 and 22 mounted to the carrier plate 20. Theoperation of carrier plate 20 in this respect is the same as in theaforementioned U.S. Reissue Pat. No. 33,237 which is again herebyincorporated by reference herein.

FIG. 7 illustrates an alternative embodiment wherein an insert 57 ofelongated conical or tubular construction is to be loaded. The insert isnot held on a mandrel. Instead, it is held in a receptacle 58 which ismounted to the structural channel 52. The insert 57 may be held in placein receptacle 58 by applying vacuum or other alternate means ofretention. As described above, the receptacle 58 on the channel 52 movesthe insert 57 to a point where mold splits 45 grasp the insert 57 andremove it from the receptacle 58. The mold splits 45 then carry theinsert 57 the remainder of the distance until it is seated on the core14. FIG. 8 shows the insert 58 lodged in its position in the cavitywhile the mold is closed.

The operation of the apparatus 10 after molding has been completed is asfollows. Once the mold is opened, the carrier plate 20 moves into placebetween the mold halves 11 and 12 with the receiving stations 21, 22opposite the mold cores 14. The mold splits holding plate 46, commonlyreferred to as a slide, then moves forward with the mold splits 45toward the receiving stations and once the molded article has partiallyentered the receiving station, the mold splits 45 continue to moveforward but also move apart from each other until the molded article isno longer in contact with the mold splits and is fully engaged in arespective receiving station. The carrier plate 20 then indexeslaterally a short distance, enough to move the molded article in thereceiving station aside from being in axial alignment with the mold core14 and to position the insert 44, 57 to be loaded in direct axialalignment with a respective mold core 14. The insert holding means 51,58 is then extended, with the insert 44, 57 toward and over the core 14until the insert is positioned a predetermined distance past the planeof the forward face of the opened mold splits. At that point, the insertholding means 51, 52, and 53 contact the mold splits by way of bumperpad forward face 56 hitting the front surface of mold split 45 andtogether they are pushed by actuating cylinder 53 to return the moldsplits 45 to the rearward position. As the rearward mold splits motiontakes place, the mold splits come slowly together gripping or envelopingall or part of the insert and are thereby interactively removing orreceiving the insert from the carrier plate insert loading means. Theinsert holding means 51, 52 and 53 are then retracted and the carrierplate 20 is removed to a location outside the mold for insert loadingonto the carrier plate and molded part unloading, as required. With theinsert now supported in place by the mold splits, the mold is closed andplastic injection is initiated.

The apparatus of the present invention has numerous advantagesassociated with it. For example, a single device, namely the carrierplate described herein, loads the mold with inserts and unloads thecompleted article from the mold. Still further, the carrier plateperforms the loading and unloading operations from a single face. Stillfurther, the apparatus mechanically grips, holds or envelopes an insertin the cavity space. Still further, the apparatus lends itself to amethod of installing an insert into a mold where the mold is dynamicallyinteractive with the insertion means of the carrier plate.

It is apparent that there has been provided in accordance with thisinvention an improved apparatus and method for producing plasticarticles which fully satisfies the objects, means, and advantages setforth hereinbefore. While the invention has been described incombination with specific embodiments thereof, it is evident that manyalternatives, modifications, and variations will be apparent to thoseskilled in the art in light of the forgoing description. Accordingly, itis intended to embrace all such alternatives, modifications, andvariations as fall within the spirit and broad scope of the appendedclaims.

What is claimed is:
 1. A method for manufacturing a molded articlehaving an insert therein, said method being characterized by the stepsof providing a first mold half having at least a mold core portion and asecond mold half having at least a mold cavity portion and defining aspace having a shape corresponding to an article to be molded;formingsaid molded article with said insert by injecting molten plasticmaterial into said space; opening the first and second mold halves bymoving the halves into an open position; linearly moving a carrier plateto a first position between both mold halves wherein said carrier plateis aligned with means for removing said molded article; removing saidmolded article and receiving said molded article into a first receivingmeans on said carrier plate; placing an insert in a desired positionrelative to said mold core portion by linearly moving said carrier plateto a second position between said mold halves wherein said carrier plateis aligned so that a means for holding said insert is in a desiredlocation relative to said mold core and cavity portions while the moldhalves are in an open position; transferring said insert to said desiredposition relative to said mold core and cavity portions; withdrawingsaid carrier plate from between said first and second mold halves; andmoving said first and second halves to a molding position wherein saidmold core portion and said mold cavity portion define said space in theshape of the article to be molded.
 2. A method according to claim 1further comprising linearly moving said carrier plate to a thirdposition wherein a second receiving means on said carrier plate isaligned with said mold core and cavity portions; andtransferring anothermolded article to said second receiving means.
 3. A method according toclaim 2 further comprising:maintaining said molded article in said firstreceiving means and cooling said molded article in said first receivingmeans while said carrier plate is being linearly moved to said thirdposition.
 4. The method according to claim 1 further comprising:saidwithdrawing step comprising withdrawing said carrier plate to a fourthposition; and releasing at least one molded part from said carrier plateand adding at least one insert onto said carrier plate when said carrierplate is in said fourth position.